Segmented antenna system for offshore radio networks and method of using same

ABSTRACT

The present invention provides a method and apparatus for a segmented antenna system. The method includes determining an orientation of a first antenna, the first antenna including a plurality of segments for transmitting and receiving signals, determining a direction from the first antenna to a second antenna capable or at least one of transmitting and receiving signals, and selecting at least one of the plurality of segments of the first antenna using the determined orientation of the first antenna and the determined direction.

RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.10/558,586, filed Nov. 29, 2005, now U.S. Pat. No. 7,383,151 and thedisclosure of which is herein incorporated by reference; which is a USnational phase application of PCT/EP04/51052, filed Jun. 7, 2004, thedisclosure of which is herein incorporated by reference; which is aninternational application of GB Application Number 0312997.0, filed Jun.6, 2003, and the disclosure of which is herein incorporated byreference.

FIELD OF THE INVENTION

This invention relates generally to a radio network, and, moreparticularly, to a segmented antenna system for an offshore radionetwork used in marine seismic surveying.

DESCRIPTION OF THE RELATED ART

Underwater seismic exploration is widely used to locate and/or surveysubterranean geological formations for hydrocarbon deposits. A surveytypically involves deploying one or more seismic sources and one or moreseismic sensors at predetermined locations. For example, a seismic cableincluding an array of seismic sensors may be deployed on the sea floorand a seismic source may be towed along the ocean's surface by a surveyvessel. The seismic sources generate acoustic waves that travel to thegeological formations beneath the ocean floor, where they are reflectedback to the seismic sensors. The seismic sensors receive the reflectedwaves, which are then processed to generate seismic data Analysis of theseismic data may indicate probable locations of geological formationsand hydrocarbon deposits.

Seismic surveys often use more than one survey vessel. For example, arecording vessel may be dedicated to receiving data collected by one ormore survey vessels. For another example, a first survey vessel,sometimes referred to as a shooting boat, may be coupled to a seismicsource that generates the acoustic signal. A second survey vessel,sometimes referred to as a recording boat, is coupled to at least oneseismic sensor that receives the reflected wave. For yet anotherexample, a deployment vessel may be used to deploy the seismic cableincluding one or more seismic sensors, a positioning vessel may be usedto position and/or re-position the deployed cables, a source vessel maybe used to tow one or more seismic sources near the deployed cables, anda recording vessel may be used to record the data. One advantage tousing multiple vessels is that a given survey area may be mapped in lesstime than would be required if the same area was mapped by a singlevessel.

When a plurality of survey vessels is used to conduct a marine seismicsurvey, a large volume of information may be transmitted among thesurvey vessels. For example, seismic data recorded and at leastpartially processed by a survey vessel may be transmitted to therecording vessel, where the seismic data may be stored for laterprocessing. For another example, seismic data may be transferred betweenthe shooting boat and the recording boat. Physically connecting thevessels, e.g. by wires or cables, is difficult, or impracticable,because of the large and variable distances separating the variousvessels. Consequently, wireless data links are used to transfer dataamong vessels in the network. For example, radio transmitters andreceivers located on the vessels are typically used to form high-speedwireless data links to transfer data between the vessels in the network.

The high-speed wireless data links are typically formed usingconventional omni-directional antennas. Vessels separated by a distancelarger than the range of the omni-directional antenna may not be able toexchange data via the high-speed wireless link. The range of thehigh-speed wireless data link may be further reduced by a number ofphysical effects such as “fading.” Fading of the radio signal is causedby reflection of the radio signal from the sea surface. Thephase-shifted reflected signal fades out the direct signal in regions ofreduced sensitivity called “dead zones” around the vessels. For example,fading of a 2.4 Ghz radio signal may create a dead zone at a range ofabout 9-10 kilometers.

Interference with other signals and/or noise may also reduce the rangeof the transmitters and/or receivers. For example, traditionalhigh-speed wireless data links may use unlicensed Industrial,Scientific, and Medical (ISM) frequency bands. The unlicensed ISM bandsmay also be used by other transmitters, such as those on board otherships in the vicinity of the survey vessels. The signals broadcast bythe other transmitters may interfere with the high-speed wireless datalink and degrade the quality of the connection. The interference maycorrupt the transferred data and/or interrupt the transfer of dataaltogether. In some cases, the data corruption and/or the interruptionof the data transfer may force a suspension of the seismic survey.

Rotating single-segment antennas have been used to extend the range ofhigh-speed data links by increasing antenna sensitivity in a reducedrange of angles in the direction of a target. However, thesingle-segment antennas suffer from at least three drawbacks. First, theposition of the target must be continuously monitored. If the target islost, the data transfer may be interrupted, and in some cases the surveymay be stopped, while the target is re-acquired. This problem isexacerbated in marine seismic surveys that use rapidly moving surveyvessels, which may also be carried by unpredictable water currents.Second, rotating single segment antennas have large numbers of movingparts, which may reduce the operational lifetime of the rotatingsingle-segment antenna and increase maintenance costs and downtime.Third, the rotating single-segment antenna can only acquire a singletarget at a time.

SUMMARY OF THE INVENTION

In one aspect of the instant invention, a method is provided for using asegmented antenna system. The method includes determining an orientationof a first antenna, the first antenna including a plurality of segmentsfor transmitting and receiving signals, determining a direction from thefirst antenna to a second antenna capable of at least one oftransmitting and receiving signals, and selecting at least one of theplurality of segments of the first antenna using the determinedorientation of the first antenna and the determined direction.

In another aspect of the present invention, a segmented antenna systemis provided. The system includes a plurality of antennae deployed at aplurality of locations, at least one of the antennae being a segmentedantenna having a plurality of segments, and a plurality of positioningsensors adapted to provide a corresponding plurality of positioningsignals indicative of the plurality of locations. The system alsoincludes at least one orientation sensor adapted to provide a signalindicative of an orientation of the at least one segmented antenna andat least one controller adapted to select at least one of the segmentsof the at least one segmented antenna using the plurality of positioningsignals and the at least one orientation signal.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be understood by reference to the followingdescription taken in conjunction with the accompanying drawings, inwhich like reference numerals identify like elements, and in which:

FIG. 1 conceptually illustrates a network of survey vessels;

FIG. 2 conceptually illustrates an exemplary embodiment of a segmentedantenna system that may be used to transmit data in the networkillustrated in FIG. 1;

FIG. 3 conceptually illustrates the operation of a selected segment of asegmented antenna such as may be found in the segmented antenna systemillustrated in FIG. 2;

FIG. 4 conceptually illustrates a method of selecting a segment of asegmented antenna that may be used by the segmented antenna systemillustrated in FIG. 2; and

FIGS. 5A and 5B conceptually illustrate a computing apparatus that maybe used to perform the method described in FIG. 4.

While the invention is susceptible to various modifications andalternative forms, specific embodiments thereof have been shown by wayof example in the drawings and are herein described in detail. It shouldbe understood, however, that the description herein of specificembodiments is not intended to limit the invention to the particularforms disclosed, but on the contrary, the intention is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Illustrative embodiments of the invention are described below. In theinterest of clarity, not all features of an actual implementation aredescribed in this specification. It will of course be appreciated thatin the development of any such actual embodiment, numerousimplementation-specific decisions must be made to achieve thedevelopers' specific goals, such as compliance with system-related andbusiness-related constraints, which will vary from one implementation toanother. Moreover, it will be appreciated that such a development effortmight be complex and time-consuming, but would nevertheless be a routineundertaking for those of ordinary skill in the art having the benefit ofthis disclosure.

FIG. 1 conceptually illustrates a plurality of survey vessels 110(1-3).For example, the survey vessels 110(1-3) may be carrying out a marineseismic survey. In one embodiment, the survey vessels 110(1-3) exchangedata via a wireless data link 115. For example, the survey vessel 110(1)may be used to gather seismic data collected by the other survey vessels110(2-3), which transmit the collected seismic data to the survey vessel110(1) via the wireless data link 115, such as a 2.4 GHz radioconnection. However, persons of ordinary skill in the art willappreciate that the plurality of survey vessels 110(1-3) may include anyvessel that communicates data via a wireless data link, including aboat, a buoy, and the like; and that the number of survey vessels110(1-3) and the frequency of the signals are not material to thepractice of the invention. The survey vessels 110(1-3) may also formwireless data links with fixed-position vessels like drilling rigs,platforms, on-shore radio towers, and the like. Furthermore, inalternative embodiments, the wireless data link 115 may be establishedbetween land-based vehicles (not shown). For example, the wireless datalink 115 may be established between a base station (not shown) and oneor more mobile vehicles (not shown) used in a land-based seismic survey.

As discussed above, in conventional practice, the wireless data link 115may be established using an omni-directional antenna (not shown)deployed on the survey vessel 110(1). The range, indicated by a dashedline 120(1) in FIG. 1, of the wireless data link 115 established using aconventional omni-directional antenna is limited by a variety offactors, including fading, interference, and the like. For example, an 8dB type omni-directional antenna has a range of about 16 kilometers.However, in the illustrated embodiment, the survey vessels 110(2-3) areoutside of the range 120(1). Consequently, the survey vessel 110(1) maynot be able to exchange data with the survey vessels 110(2-3) via thewireless data link 115 established using a conventional omni-directionalantenna.

A segmented antenna system 130(1) in accordance with the presentinvention is therefore deployed on the survey vessel 110(1) to establishthe wireless data link 115 to survey vessels 110(2) within a range120(2). In operation, the segmented antenna system 130(1) determines anorientation, indicated by the arrow 150(1), of the segmented antenna140(1). For example, the segmented antenna system 130(1) may determinethe orientation 150(1) of the segmented antenna 140(1) relative to trueNorth. The segmented antenna system 130(1) also determines a directionfrom the segmented antenna 140(1) to a target. For example, thesegmented antenna system 130(1) may determine the direction 160(1) fromthe survey vessel 110(1) to the survey vessel 110(2). Similarly, if asegmented antenna system 130(2) is deployed on the survey vessel 110(2),then the segmented antenna system 130(2) on the survey vessel 110(2) maydetermine the direction 160(2) from the survey vessel 110(2) to thesurvey vessel 110(1).

The segmented antenna system 130(1) includes a segmented antenna 140(1)for transmitting and/or receiving signals to and from a target, e.g. thesurvey vessels 110(2-3). By establishing the wireless data link 115using the determined orientation 150(1) and the determined direction160(1), as described in detail below, the range 120(2) of the wirelessdata link 115 formed with the segmented antenna 140(1) may exceed therange 120(1). For example, the segmented antenna system 130(1) may beable to establish the wireless data link 115 out to a range 120(2) of upto about 20 kilometers at a frequency of about 2.4 GHz. However, it willbe appreciated by those of ordinary skill in the art that the exactrange 120(2), may depend on a variety of factors including, but notlimited to, the height at which the segmented antenna system 130(1) isdeployed.

In one set of alternative embodiments, segmented antenna systems130(2-3) having segmented antennas 140(2-3) may also be deployed on thesurvey vessels 110(2-3). Deploying the segmented antenna systems130(2-3) on the survey vessels 110(2-3), and using them in the mannerdescribed below, may further extend the range 120(2) over which thewireless data link 115 may be established. For example, the segmentedantenna system 130(1) may be able to establish the wireless data link115 with the segmented antenna system 130(2) out to a range of up toabout 30 kilometers at a frequency of about 2.4 GHz.

FIG. 2 conceptually illustrates an exemplary embodiment of the segmentedantenna system 130(1) including the segmented antenna 140(1). Thesegmented antenna 140(1) includes a plurality of segments 200 (not allindicated) capable of transmitting and/or receiving signals. Forexample, in one embodiment, each of the plurality of segments 200 mayinclude a radio transmitter/receiver (not shown) capable of transmittingand/or receiving radio signals. In the illustrated embodiment, thesegmented antenna 130(1) includes 16 segments 200 that may transmitand/or receive signals within partially overlapping angles that subtendabout 26.degree. and overlap by about 4.degree. Thus, the segmentedantenna 140(1) may transmit and/or receive signals throughout about360.degree. However, persons having benefit of the present disclosurewill appreciate that the number, degree of overlap, and angular extentof the segments 200 is a matter of design choice.

Although not necessary for the practice of the present invention, in oneembodiment, a plurality of the segments 200 may transmit and/or receiveseparate signals concurrently with each other. For example, the segments200 may each include a radio transmitter/receiver (not shown) that iscapable of transmitting and/or receiving signals independently of, andconcurrently with, the other radio transmitter/receivers. In theillustrated embodiment, the segmented antenna 130(1) may be capable offorming up to 16 concurrent wireless data links with up to 16 separatevessels, such as the survey vessels 110(1-3) shown in FIG. 1.

In the embodiment illustrated in FIG. 2, an orientation sensor 210 iscoupled to a controller 215 in the segmented antenna system 130(1). Theorientation sensor 210 is capable of determining the orientation 150(1)of the segmented antenna 140(1). For example, when the segmented antenna140(1) is deployed on the survey vessel 10(1) shown in FIG. 1, theorientation sensor 210 is capable of determining the orientation 150(1)of the segmented antenna 140(1) by determining a heading of the surveyvessel 110(1). In one embodiment, the orientation sensor 210 is agyrocompass that determines the heading of the survey vessel 110(1)relative to true North. For example, in one embodiment, the gyrocompass210 may use an NMEA 0183 data interface or, in an alternativeembodiment, an NMEA 2000 data interface having a high-speed option.However, in alternative embodiments, the orientation sensor 210 may notinclude a gyrocompass and may instead determine the orientation of thesegmented antenna system 130(1) using GPS positioning information. Inother alternative embodiments, the orientation sensor 210 may determinethe orientation of the segmented antenna system 130(1) using any of avariety of compass sensors known to those of ordinary skill in the art.The orientation sensor 210 is also capable of forming a signalindicative of one or more determined parameters, such as the determinedorientation 150(1), and providing the signal indicative of the one ormore determined parameters, such as the determined orientation 150 (1),to the controller 215.

In the illustrated embodiment, the controller 215 in the segmentedantenna system 130(1) determines the direction to the target using aposition sensor 220 and a receiver 225 that are coupled to thecontroller 215. In one embodiment, the position sensor 220 is a portionof a Global Positioning System (“GPS”). For example, the position sensor220 may be a GPS receiver that provides a signal indicative of thelocation of the segmented antenna system 130(1), such as a standardizedNA-182 output, to the controller 215. The position sensor 220 may alsoprovide an identification signal associated with the segmented antennasystem 130(1). In one embodiment, the identification signal isassociated with the location signal so that the location signalscorresponding to multiple segmented antenna systems 130(1-3) may bedistinguished from each other.

The receiver 225 receives a signal transmitted by the target indicativeor the target's location and provides the location information to thecontroller 215. In one embodiment, the signal is transmitted to thereceiver 225 on a frequency band that is different than the band that isused by the segmented antennas 140(1-3) to establish the wireless datalink. For example, the survey vessel 110(2) may transmit a signalcontaining GPS information indicative of the location of the surveyvessel 110(2) to the survey vessel 110(1) in a IHF frequency band whilethe wireless data link is established at about 2.4 GHz. However, thereceiver 225 is not limited to receiving signals transmitted in the UHFfrequency band. In alternative embodiments, the location information maybe transmitted to the receiver at about 900 MHz, about 450 MHz, VHFfrequencies, and the like. In another alternative embodiment, thelocation information may be transmitted to the receiver 225 via asatellite link.

The wireless data link established by transmitting the location signalon the frequency band that is different than the band that is used bythe segmented antennas 140(1-3) may be more robust For example, aninterrupted wireless data link may be re-established more quickly bytransmitting the location signal to the segmented antenna system140(1-3) on the frequency band that is different than the band that isused by the segmented antennas 140(1-3) to form the wireless data link.

Although the embodiment of the segmented antenna system 130(1)illustrated in FIG. 2 determines the direction from the segmentedantenna 140(1) to the target using the positional information providedby the position sensor 220 and the receiver 225, the present inventionis not limited to using positional information such as GPS data. Inalternative embodiments, any desirable method of determining thedirection to the target, such as radar sensing by radar devices (notshown) located on the survey vessels 110(1-3), may be used.

FIG. 3 conceptually illustrates the operation of a selected segment 300,indicated by cross-hatching, of the segmented antenna 140(1). In theillustrated embodiment, an orientation 305 of a reference segment 307 ofthe segmented antenna 140(1) is determined. However, in alternativeembodiments, the orientation 305 of the segmented antenna 140(1) may beapproximately equal to a heading of any feature that has a knowngeometric relation some portion of the segmented antenna 140(1). Adirection 310 to the vessel 315 is also determined.

The controller 215 then uses the determined orientation 305 of thesegmented antenna 140(1) and the determined direction 310 to select asegment 300, which may be used to form the wireless data link. In theillustrated embodiment, the controller 215 may select a segment 300 bydetermining that the direction 310 to the vessel 315 lies within atransmission and/or reception angle, indicated in FIG. 3 by the dashedlines 320(1-2). For example, the controller 215 may select the segment300 by comparing the relative angle between the determined orientation305 and the determined direction 310 with the relative angle between thereference segment 307 and the selected segment 300. The selected segment300 may then be used to establish a wireless data link between thesegmented antenna 140(1) and the vessel 315.

Referring back to FIG. 2, in one set of embodiments, as described above,the segments 200 may overlap, in which case a hysteresis may be used toselect the appropriate segment 200. For example, if the segments 200overlap by approximately 4.degree., a survey vessel 110 (2-3) crossingthrough the overlap will be assigned to a new segment 200 once it haspassed approximately 3 degrees into the overlap as measured from theentry side of the new segment 200. To be re-assigned to the previoussegment 200, the survey vessel 110(2-3) may move back to 1 degree intothe overlap measured from the same side of the new segment 200, or 3degrees measured from the entry side of the previous segment 200.However, it will be appreciated by those of ordinary skill in the art,that the overlap is not necessary for the practice of the presentinvention. In various alternative embodiments, there may be no overlapbetween the segments 200. Furthermore, it will be appreciated by thoseof ordinary skill in the art, a hysteresis is not necessary to thepractice of the present invention. Any of a variety of methods ofassigning the segments 200 may be used.

In one alternative embodiment, sometimes referred to as an “adaptivearray,” a plurality of segments 200 may be selected to form the wirelessdata link for transmission and/or reception of signals. The selection ofthe number of segments 200 may depend on the desiredtransmission/reception range of the wireless data link. For example, ifthe range 120(1) shown in FIG. 1 is reduced, a larger number of segments200 may be used for transmission and/or reception. In one embodiment,the plurality of segments 200 may be selected by selecting a centralsegment 200 and one or more segments 200 adjacent the central segment200.

A signal processing unit 230 is coupled to the segmented antenna 140(1).When signals are received via the wireless data link, the segmentedantenna 140(1) may provide the received signals to the signal processingunit 230, which may at least partially process the data. The signalprocessing unit 230 may also provide a signal to the segmented antenna140(1), which may be transmitted via the wireless data link. In oneembodiment, the signal processing unit 230 includes a filter 235. Forexample, the filer 235 may be a narrow-band filter centred on afrequency of about 2442 MHz and having a 3 db bandwidth of about 24 MHz.Noise in the wireless data link may be reduced by incorporating thefilter 235 in the signal processing unit 230.

In one embodiment, the segmented antenna system 130 may include anantenna 240 vertically displaced from the segmented antenna 140. Forexample, the antenna 240 may be a conventional omni-directional antennadeployed above the segmented antenna 140(1) on a mast (not shown). Thesignal processing unit 230 may reduce multi-path fading caused bysea-surface reflection of the wireless data link signal by combining thesignals received by the segmented antenna 140(1) and the antenna 240 ina manner well known to persons of ordinary skill in the art.Consequently, the wireless data link formed using the segmented antennasystem 130(1) and the antenna 240 may have not have gaps around a range120(3), allowing the wireless data link to be formed between the surveyvessel 110(1) and the survey vessel 110(3), as shown in FIG. 1. Forexample, the 2.4 GHz dead zone at 9-10 kilometers may be reduced, oreven removed, thereby allowing a wireless data link to be formed withthe survey vessel 110(3) at the range 120(3) of about 9-10 kilometers.However, it will be appreciated that the antenna 240 is optional and notnecessary for the practice of the present invention.

FIG. 4 conceptually illustrates a method of selecting the segment 300 ofthe segmented antenna 140(1) that may be used by the segmented antennasystem 130(1). The controller 215 determines (at 400) the orientation150(1), e.g. relative to magnetic North, of the segmented antenna 140(1)and determines (at 410) the direction 160(1) from the segmented antenna140(1) to a target As discussed in detail above, the direction 160(1)may be determined using the GPS locations of the survey vessel 110(1-3).Furthermore, in various alternative embodiments, the target may be anomni-directional antenna, another segmented antenna 140(2-3), or otherlike transmission and/or reception device.

The controller 215 then selects (at 420) at least one segment 200 of thesegmented antenna 130(1) using the determined orientation 150(1) and thedetermined direction 160(1). A wireless data link may then be formed (at430) using the selected segment 200 so that signals may be transmittedand/or received using the selected segment 200; By selecting (at 420) atleast one appropriate segment 200 and forming (at 430) the wireless datalink using the at least one segment 200 according to the above method,the range of the wireless data link may be extended and, in someembodiments, gaps in the range of the wireless data link may be reducedand/or removed, as previously discussed. Moreover, the minimal number ofmoving parts required to operate the segmented antenna system 130(1)according to the above method allows moving targets to be acquiredand/or reacquired in a shorter time relative to antennae that rotate toacquire targets. In addition, the segmented antenna system 130(1) mayhave an increased operational lifetime and reduced maintenance costs anddowntime relative to systems that utilize more moving parts.

The controller 215 may be embodied, at least in part, in a computingapparatus 500 that may be used to perform the aforementioned operations,as illustrated in FIGS. 5A and 5B. The computing apparatus 500 includesa processor 505 communicating with some storage 510 over a bus system515. The storage 510 may include a hard disk and/or random access memory(“RAM”) and/or removable storage such as a floppy magnetic disk 517 andan optical disk 520. The storage 510 is encoded with a data structure525 storing the signals collected as discussed above, an operatingsystem 530, user interface software 535, and an application 565. Theuser interface software 535, in conjunction with a display 540,implements a user interface 545. The user interface 545 may includeperipheral I/O devices such as a key pad or keyboard 550, a mouse 555,or a joystick 560. The processor 505 runs under the control of theoperating system 530, which may be practically any operating systemknown to the art. The application 565 is invoked by the operating system530 upon power up, reset, or both, depending on the implementation ofthe operating system 530.

As discussed above, data collected during the marine seismic survey maybe communicated to the computing apparatus 500 via any storage medium,including, but not limited to, magnetic and optical storage media suchas recording tape, magnetic disks, compact disks, and DVDs. The datacollected during the marine seismic survey may also be communicateddirectly to the computing apparatus 500 and stored in the storage 510via wires, cables, wireless data links, and the like. Some portions ofthe detailed descriptions herein are consequently presented in terms ofa software implemented process involving symbolic representations ofoperations on data bits within a memory in a computing system or acomputing device. These descriptions and representations are the meansused by those in the art to most effectively convey the substance oftheir work to others skilled in the art. The process and operationrequire physical manipulations of physical quantities. Usually, thoughnot necessarily, these quantities take the form of electrical, magnetic,or optical signals capable of being stored, transferred, combined,compared, and otherwise manipulated. It has proven convenient at times,principally for reasons of common usage, to refer to these signals asbits, values, elements, symbols, characters, terms, numbers, or thelike.

It should be borne in mind, however, that all of these and similar termsare to be associated with the appropriate physical quantities and aremerely convenient labels applied to these quantifies. Unlessspecifically stated or otherwise as may be apparent, throughout thepresent disclosure, these descriptions refer to the action and processesof an electronic device, that manipulates and transforms datarepresented as physical (electronic, magnetic, or optical) quantitieswithin some electronic device's storage into other data similarlyrepresented as physical quantities within the storage, or intransmission or display devices. Exemplary of the terms denoting such adescription are, without limitation, the terms “processing,”“computing,” “calculating,” “determining,” “displaying,” and the like.

Note also that the software implemented aspects of the invention aretypically encoded on some form of program storage medium or implementedover some type of transmission medium. The program storage medium may bemagnetic (e.g., a floppy disk or a hard drive) or optical (e.g., acompact disk read only memory, or “CD ROM”), and may be read only orrandom access. Similarly, the transmission medium may be twisted wirepairs, coaxial cable, optical fibre, or some other suitable transmissionmedium known to the art The invention is not limited by these aspects ofany given implementation.

The particular embodiments disclosed above are illustrative only, as theinvention may be modified and practiced in different but equivalentmanners apparent to those skilled in the art having the benefit of theteachings herein. Furthermore, no limitations are intended to thedetails of construction or design herein shown, other than as describedin the claims below. It is therefore evident that the particularembodiments disclosed above may be altered or modified and all suchvariations are considered within the scope and spirit of the invention.Accordingly, the protection sought herein is as set forth in the claimsbelow.

1. An apparatus, comprising: a segmented antenna having a plurality ofsegments, each segment being capable of transmitting and receivingsignals; a position sensor adapted to provide a positioning signalindicative of a position of the segmented antenna; an orientation sensoradapted to provide an orientation signal indicative of an orientation ofthe segmented antenna; a receiver adapted to receive a targetpositioning signal indicative of a position of a target antenna; and acontroller adapted to select at least one of the segments using thepositioning signal, the target positioning signal, and the orientationsignal.
 2. The apparatus of claim 1, wherein each segment is adapted toform a wireless data link between the segmented antenna and the targetantenna.
 3. The apparatus of claim 2, wherein the segmented antennacomprises 16 segments.
 4. The apparatus of claim 3, wherein each segmentis capable of transmitting and receiving signals within an angle ofabout 26°, and wherein the angles overlap by about 4°.
 5. The apparatusof claim 1, wherein the controller is adapted to select at least one ofthe segments using a hysteresis.
 6. The apparatus of claim 1, whereinthe receiver is adapted to receive signals in at least one of a UHFband, a VHF band, and a satellite link.
 7. The apparatus of claim 1,wherein the position sensor is a Global Positioning System device. 8.The apparatus of claim 1, wherein the orientation sensor is agyrocompass or a compass.
 9. The apparatus of claim 1, wherein thetarget antenna is an omni-directional antenna.
 10. The apparatus ofclaim 1, further comprising an antenna vertically displaced from theantenna.
 11. The apparatus of claim 10, wherein the vertically-displacedantenna is vertically displaced from the segmented antenna by about 6meters.
 12. The apparatus of claim 10, further comprising a signalprocessing unit adapted to combine signals received from the segmentedantenna and the vertically-displaced antenna.
 13. The apparatus of claim12, wherein the signal processing unit comprises a band-pass filter. 14.The apparatus of claim 10, wherein the vertically-displaced antenna isan omni-directional antenna.
 15. The apparatus of claim 1, wherein theorientation of the segmented antenna is a heading of a vessel.
 16. Anaparatus, comprising: a segmented antenna having a pluralitv ofsegments, each segment being capable of at least one of transmitting andreceiving signals; a position sensor adapted to provide a positioningsignal indicative of a position of the segmented antenna; an orientationsensor adapted to provide an orientation signal indicative of anorientation of the segmented antenna; a receiver adapted to receive atarget positioning signal indicative of a position of a target antenna;a controller adapted to select at least one of the segments using thepositioning signal, the target positioning signal, and the orientationsignal; and wherein the target antenna comprises a plurality ofsegments, each segment being capable of at least one of transmitting andreceiving signals, and further comprising: a target position sensoradapted to provide the target positioning signal indicative of theposition of the target antenna; a target orientation sensor adapted toprovide a target orientation signal indicative of an orientation of thetarget antenna; a target receiver adapted to receive the positioningsignal indicative of the position of the segmented antenna; and a targetcontroller adapted to select at least one of the segments of the targetantenna using the positioning signal, the target positioning signal, andthe target orientation signal.
 17. A system, comprising: a plurality ofantennae deployed at a plurality of locations, at least one of theantennae being a segmented antenna having a plurality of segments, eachsegment being capable of transmitting and receiving signals; a pluralityof positioning sensors adapted to provide a corresponding plurality ofpositioning signals indicative of the plurality of locations; at leastone orientation sensor adapted to provide a signal indicative of anorientation of the at least one segmented antenna; and at least onecontroller adapted to select at least one of the segments of the atleast one segmented antenna using the plurality of positioning signalsand the at least one orientation signal.
 18. The system of claim 17,wherein the at least one controller is adapted to form a wireless datalink between the segmented antenna and at least one of the plurality ofantennas on a first frequency band.
 19. The system of claim 18, furthercomprising at least one receiver coupled to the at least one controller,the receiver being adapted to receive the plurality of positioningsignals via a second frequency band different than the first frequencyband and provide the plurality of positioning signals to the controller.20. The system of claim 19, further comprising at least one antennavertically displaced from the at least one segmented antenna.
 21. Thesystem of claim 20, further comprising a signal processing unit adaptedto combine a signal from the vertically-displaced antenna and a signalfrom the at least one segmented antenna.
 22. The system of claim 21,wherein the signal processing unit comprises a band-pass filter.
 23. Thesystem of claim 17, wherein the plurality of locations include at leastone of a moving vehicle and a fixed-position structure.
 24. The systemof claim 23, wherein the moving vehicle comprises at least one of a shipand a buoy.
 25. The system of claim 23, wherein the fixed-positionstructure includes at least one of a landbased tower and an off-shoreplatform.
 26. The system of claim 17, wherein the plurality ofpositioning sensors are a plurality of Global Positioning Systems. 27.The system of claim 17, wherein the at least one orientation sensor is agyrocompass or a compass.